scholarly journals Influence of tendon slack on electromechanical delay in the human medial gastrocnemius in vivo

2004 ◽  
Vol 96 (2) ◽  
pp. 540-544 ◽  
Author(s):  
Tetsuro Muraoka ◽  
Tadashi Muramatsu ◽  
Tetsuo Fukunaga ◽  
Hiroaki Kanehisa
Keyword(s):  
Electrical Stimulation ◽  
Ankle Joint ◽  
Joint Angle ◽  
Joint Torque ◽  
Medial Gastrocnemius ◽  
Joint Angles ◽  
Electromechanical Delay ◽  
Tendon Length ◽  
Slack Length

The purpose of this study was to clarify the influence of muscle-tendon complex stretch on electromechanical delay (EMD) in terms of the extent of tendon slack in the human medial gastrocnemius (MG). EMD and MG tendon length were measured at each of five ankle joint angles (-30, -20, -10, 0, and 5°: positive values for dorsiflexion) using percutaneous electrical stimulation and ultrasonography, respectively. The extent of MG tendon slack was calculated as MG tendon length shortening, standardized with MG tendon slack length obtained at the joint angle (-16° ± 5°) where the passive ankle joint torque was zero. EMD at -30° (19.2 ±2.2 ms) and -20° (17.2 ± 1.3 ms) was significantly greater than that at -10° (16.0 ±2.3 ms), 0° (15.0 ±1.4 ms), and 5° (14.8 ±1.4 ms), and at 0 and 5°, respectively. The relative EMD, normalized with the maximal EMD for each subject, decreased dependent on the extent of decrease in MG tendon slack. There were no significant differences in EMD among the joint angles (-10, 0, and 5°) where MG tendon slack was taken up. These results suggest that the extent of tendon slack is an important factor for determining EMD.

Tendon elongation influences the amplitude of interpolated doublets in the assessment of activation in elderly men

2005 ◽  
Vol 98 (1) ◽  
pp. 221-226 ◽  
Author(s):  
Christopher I. Morse ◽  
Jeanette M. Thom ◽  
Karen M. Birch ◽  
Marco V. Narici
Keyword(s):  
Ankle Joint ◽  
Joint Angle ◽  
Plantar Flexion ◽  
Negative Association ◽  
Plantar Flexors ◽  
Joint Angles ◽  
Elderly Men ◽  
Electromechanical Delay ◽  
Tendon Elongation ◽  
Voluntary Contractions

This study investigated the influence of tendon elongation (TE) on postcontraction doublet (PCD) torque in the assessment of activation in the plantar flexors of nine elderly men (EM, age 73.7 ± 3.6 yr) and nine young men (YM, age 24.7 ± 4.7 yr). Plantar flexion maximal voluntary contractions (MVC) and activation were assessed at ankle joint angles of −20° (dorsiflexion), 0°, and 20° (plantar flexion). Across the ankle joint angles tested, compared with YM, the EM had a 36–49% lower plantar flexion MVC ( P < 0.01), TE was greater by 25–31% ( P < 0.01), and electromechanical delay was 65–108% greater ( P < 0.01). Activation (PCD torque to interpolated doublet torque) was 15% lower in EM compared with YM at −20° ( P < 0.05), but no different at 0 and 20°. In the EM, PCD torque relative to MVC torque was significantly lower at 20° compared with 0° ( P < 0.05). Electromechanical delay was positively correlated with TE ( R2 = 0.489, P < 0.01). In conclusion, this investigation demonstrates that, although a negative association exists between TE and PCD torque, the consequence of a greater TE on the estimation of activation in EM is negligible. This is due to a greater influence of ankle joint angle on the occlusion of a superimposed doublet, which counteracts the lesser influence of joint angle on TE and PCD torque. However, a greater TE in EM was found to significantly increase electromechanical delay, which is expected to influence the time needed for postural readjustments.

scholarly journals The Application of Deep Convolutional Neural Networks to Ultrasound for Modelling of Dynamic States within Human Skeletal Muscle

2017 ◽  
Author(s):  
Ryan J. Cunningham ◽  
Peter J. Harding ◽  
Ian D. Loram
Keyword(s):  
Skeletal Muscle ◽  
Joint Angle ◽  
Region Of Interest ◽  
Image Understanding ◽  
Joint Torque ◽  
Medial Gastrocnemius ◽  
Ultrasound Images ◽  
Deep Convolutional Neural Networks ◽  
Segmented Images

AbstractThis paper concerns the fully automatic direct in vivo measurement of active and passive dynamic skeletal muscle states using ultrasound imaging. Despite the long standing medical need (myopathies, neuropathies, pain, injury, ageing), currently technology (electromyography, dynamometry, shear wave imaging) provides no general, non-invasive method for online estimation of skeletal intramuscular states. Ultrasound provides a technology in which static and dynamic muscle states can be observed non-invasively, yet current computational image understanding approaches are inadequate. We propose a new approach in which deep learning methods are used for understanding the content of ultrasound images of muscle in terms of its measured state. Ultrasound data synchronized with electromyography of the calf muscles, with measures of joint torque/angle were recorded from 19 healthy participants (6 female, ages: 30 ± 7.7). A segmentation algorithm previously developed by our group was applied to extract a region of interest of the medial gastrocnemius. Then a deep convolutional neural network was trained to predict the measured states (joint angle/torque, electromyography) directly from the segmented images. Results revealed for the first time that active and passive muscle states can be measured directly from standard b-mode ultrasound images, accurately predicting for a held out test participant changes in the joint angle, electromyography, and torque with as little error as 0.022°, 0.0001V, 0.256Nm (root mean square error) respectively.

scholarly journals Estimation of absolute states of human skeletal muscle via standard B-mode ultrasound imaging and deep convolutional neural networks

2020 ◽  
Vol 17 (162) ◽  
pp. 20190715 ◽  
Author(s):  
Ryan J. Cunningham ◽  
Ian D. Loram
Keyword(s):  
Neural Networks ◽  
Skeletal Muscle ◽  
Joint Angle ◽  
Region Of Interest ◽  
Joint Moment ◽  
Medial Gastrocnemius ◽  
Deep Convolutional Neural Networks ◽  
Non Invasive ◽  
Segmented Images

The objective is to test automated in vivo estimation of active and passive skeletal muscle states using ultrasonic imaging. Current technology (electromyography, dynamometry, shear wave imaging) provides no general, non-invasive method for online estimation of skeletal muscle states. Ultrasound (US) allows non-invasive imaging of muscle, yet current computational approaches have never achieved simultaneous extraction or generalization of independently varying active and passive states. We use deep learning to investigate the generalizable content of two-dimensional (2D) US muscle images. US data synchronized with electromyography of the calf muscles, with measures of joint moment/angle, were recorded from 32 healthy participants (seven female; ages: 27.5, 19–65). We extracted a region of interest of medial gastrocnemius and soleus using our prior developed accurate segmentation algorithm. From the segmented images, a deep convolutional neural network was trained to predict three absolute, drift-free components of the neurobiomechanical state (activity, joint angle, joint moment) during experimentally designed, simultaneous independent variation of passive (joint angle) and active (electromyography) inputs. For all 32 held-out participants (16-fold cross-validation) the ankle joint angle, electromyography and joint moment were estimated to accuracy 55 ± 8%, 57 ± 11% and 46 ± 9%, respectively. With 2D US imaging, deep neural networks can encode, in generalizable form, the activity–length–tension state relationship of these muscles. Observation-only, low-power 2D US imaging can provide a new category of technology for non-invasive estimation of neural output, length and tension in skeletal muscle. This proof of principle has value for personalized muscle assessment in pain, injury, neurological conditions, neuropathies, myopathies and ageing.

scholarly journals Static forces and moments generated in the insect leg: comparison of a three-dimensional musculo-skeletal computer model with experimental measurements

1995 ◽  
Vol 198 (6) ◽  
pp. 1285-1298 ◽  
Author(s):  
R Full ◽  
A Ahn
Keyword(s):  
Joint Angle ◽  
Three Dimensional ◽  
Joint Moment ◽  
Maximum Force ◽  
Moment Arm ◽  
Joint Angles ◽  
Extensor Muscles ◽  
Large Joint ◽  
Muscle Moments

As a first step towards the integration of information on neural control, biomechanics and isolated muscle function, we constructed a three-dimensional musculo-skeletal model of the hind leg of the death-head cockroach Blaberus discoidalis. We tested the model by measuring the maximum force generated in vivo by the hind leg of the cockroach, the coxa&shy;femur joint angle and the position of this leg during a behavior, wedging, that was likely to require maximum torque or moment production. The product of the maximum force of the leg and its moment arm yielded a measured coxa&shy;femur joint moment for wedging behavior. The maximum musculo-apodeme moment predicted by summing all extensor muscle moments in the model was adequate to explain the magnitude of the coxa&shy;femur joint moment produced in vivo by the cockroach and occurred at the same joint angle measured during wedging. Active isometric muscle forces predicted from our model varied by 3.5-fold among muscles and by as much as 70 % with joint angle. Sums of active and passive forces varied by less than 3.5 % over the entire range of possible joint angles (0&shy;125 &deg;). Maximum musculo-apodeme moment arms varied nearly twofold among muscles. Moment arm lengths decreased to zero and switched to the opposite side of the center of rotation at joint angles within the normal range of motion. At large joint angles (&gt;100 &deg;), extensors acted as flexors. The effective mechanical advantage (musculo-apodeme moment arm/leg moment arm = 0.10) resulted in the six femoral extensor muscles of the model developing a summed force (1.4 N) equal to over 50 times the body weight. The model's three major force-producing extensor muscles attained 95 % of their maximum force, moment arm and moment at the joint angle used by the animal during wedging.

scholarly journals Passive Mechanical Properties of Human Medial Gastrocnemius and Soleus Musculotendinous Unit

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ruoli Wang ◽  
Shiyang Yan ◽  
Marius Schlippe ◽  
Olga Tarassova ◽  
Gaia Valentina Pennati ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Achilles Tendon ◽  
Three Dimensional ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Passive Stretching ◽  
Slack Length ◽  
In Vivo Characterization ◽  
Passive Stretch

The in vivo characterization of the passive mechanical properties of the human triceps surae musculotendinous unit is important for gaining a deeper understanding of the interactive responses of the tendon and muscle tissues to loading during passive stretching. This study sought to quantify a comprehensive set of passive muscle-tendon properties such as slack length, stiffness, and the stress-strain relationship using a combination of ultrasound imaging and a three-dimensional motion capture system in healthy adults. By measuring tendon length, the cross-section areas of the Achilles tendon subcompartments (i.e., medial gastrocnemius and soleus aspects), and the ankle torque simultaneously, the mechanical properties of each individual compartment can be specifically identified. We found that the medial gastrocnemius (GM) and soleus (SOL) aspects of the Achilles tendon have similar mechanical properties in terms of slack angle (GM: − 10.96 ° ± 3.48 ° ; SOL: − 8.50 ° ± 4.03 ° ), moment arm at 0° of ankle angle (GM: 30.35 ± 6.42  mm; SOL: 31.39 ± 6.42  mm), and stiffness (GM: 23.18 ± 13.46  Nmm-1; SOL: 31.57 ± 13.26  Nmm-1). However, maximal tendon stress in the GM was significantly less than that in SOL (GM: 2.96 ± 1.50  MPa; SOL: 4.90 ± 1.88  MPa, p = 0.024 ), largely due to the higher passive force observed in the soleus compartment (GM: 99.89 ± 39.50  N; SOL: 174.59 ± 79.54  N, p = 0.020 ). Moreover, the tendon contributed to more than half of the total muscle-tendon unit lengthening during the passive stretch. This unequal passive stress between the medial gastrocnemius and the soleus tendon might contribute to the asymmetrical loading and deformation of the Achilles tendon during motion reported in the literature. Such information is relevant to understanding the Achilles tendon function and loading profile in pathological populations in the future.

scholarly journals Modified Ankle Joint Neuromechanics during One-Legged Heel Raise Test after an Achilles Rupture and Its Associations with Jumping

2021 ◽  
Vol 11 (5) ◽  
pp. 2227
Author(s):  
Kao-Shang Shih ◽  
Pei-Yu Chen ◽  
Wen-Ling Yeh ◽  
Hsiao-Li Ma ◽  
Chui-Jia Farn ◽  
...  
Keyword(s):  
Ankle Joint ◽  
Dynamic Characteristics ◽  
Muscle Activation ◽  
Joint Angle ◽  
Reaction Force ◽  
Medial Gastrocnemius ◽  
Jumping Performance ◽  
The One ◽  
Lower Ankle Joint ◽  
Kinematics And Kinetics

This study had two purposes. The first purpose of the study was to compare the electromyographic(EMG) and dynamic characteristics in injured and non-injured legs during the one-legged heel-raise test after a unilateral Achilles repair. The second purpose was to determine the correlations between the EMG results and the dynamic characteristics and between the characteristics in the eccentric phase and jumping distance. Twenty-six participants who underwent an Achilles repair between 4 and 12 months prior to the measurement were recruited to perform the following bilateral tests: (1) one-legged heel-raise test with measurements of muscle activation, kinematics, and kinetics and (2) one-legged forward jumping. During the heel-raise exercise, there were increases of the EMG amplitudes in the soleus and tibialis anterior muscles, lower ankle joint angle and angular velocity, lower normalized ground reaction force, and mechanical work in the repaired legs in comparison to the non-injured legs. The EMG results of the medial gastrocnemius and soleus muscles correlated with the dynamic results (rs = 0.467 and −0.537). Furthermore, the dynamic data in the eccentric phase were correlated with the jumping performance (rs = 0.575 and −0.471). It is concluded the soleus muscle undergoes neuromechanical changes, including changes in EMG and dynamic characteristics, and changes affecting jumping performance.

Relationships between muscle size and hardness of the medial gastrocnemius at different ankle joint angles in young men

2012 ◽  
Vol 53 (3) ◽  
pp. 307-311 ◽  
Author(s):  
Ryota Akagi ◽  
Kentaro Chino ◽  
Michiko Dohi ◽  
Hideyuki Takahashi
Keyword(s):  
Ankle Joint ◽  
Young Men ◽  
Medial Gastrocnemius ◽  
Muscle Size ◽  
Joint Angles

scholarly journals Association between medial gastrocnemius muscle-tendon unit architecture and ankle dorsiflexion range of motion with and without consideration of slack angle

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0248125
Author(s):  
Kosuke Hirata ◽  
Hiroaki Kanehisa ◽  
Naokazu Miyamoto
Keyword(s):  
Shear Modulus ◽  
Range Of Motion ◽  
Ankle Joint ◽  
Joint Angle ◽  
Pennation Angle ◽  
Medial Gastrocnemius ◽  
Fascicle Length ◽  
Joint Flexibility ◽  
Anatomical Position ◽  
Maximal Angle

Joint flexibility is theoretically considered to associate with muscle-tendon unit (MTU) architecture. However, this potential association has not been experimentally demonstrated in humans in vivo. We aimed to identify whether and how MTU architectural parameters are associated with joint range of motion (RoM), with a special emphasis on slack angle. The fascicle length, pennation angle, tendinous tissue length, MTU length, and shear modulus of the medial gastrocnemius (MG) were assessed during passive ankle dorsiflexion using ultrasound shear wave elastography in 17 healthy males. During passive dorsiflexion task, the ankle joint was rotated from 40° plantar flexion to the maximal dorsiflexion joint angle at which each subject started experiencing pain. From the ankle joint angle-shear modulus relationship, the angle at which shear modulus began to rise (slack angle) was calculated. Two dorsiflexion RoMs were determined as follows; 1) range from the anatomical position to maximal angle (RoManat-max) and 2) range from the MG slack angle to maximal angle (RoMslack-max). The MTU architectural parameters were analyzed at the anatomical position and MG slack angle. The resolved fascicle length (fascicle length × cosine of pennation angle) and ratios of resolved fascicle or tendinous tissue length to MTU length measured at the MG slack angle significantly correlated with the RoMslack-max (r = 0.491, 0.506, and -0.506, respectively). Any MTU architectural parameters assessed at the anatomical position did not correlate with RoManat-max or RoMslack-max. These results indicate that MTUs with long fascicle and short tendinous tissue are advantageous for joint flexibility. However, this association cannot be found unless MTU architecture and joint RoM are assessed with consideration of muscle slack.

The Dynamics of Postural Sway Cannot Be Captured Using a One-Segment Inverted Pendulum Model: A PCA on Segment Rotations During Unperturbed Stance

2008 ◽  
Vol 100 (6) ◽  
pp. 3197-3208 ◽  
Author(s):  
Ilona J. Pinter ◽  
Roos van Swigchem ◽  
A. J. Knoek van Soest ◽  
Leonard A. Rozendaal
Keyword(s):  
Postural Control ◽  
Ankle Joint ◽  
Inverted Pendulum ◽  
Joint Angle ◽  
Postural Sway ◽  
Lower Leg ◽  
Joint Angles ◽  
Inverted Pendulum Model ◽  
Pendulum Model ◽  
Ankle Angle

Research on unperturbed stance is largely based on a one-segment inverted pendulum model. Recently, an increasing number of studies report a contribution of other major joints to postural control. Therefore this study evaluates whether the conclusions originating from the research based on a one-segment model adequately capture postural sway during unperturbed stance. High-pass filtered kinematic data (cutoff frequency 1/30 Hz) obtained over 3 min of unperturbed stance were analyzed in different ways. Variance of joint angles was analyzed. Principal-component analysis (PCA) was performed on the variance of lower leg, upper leg, and head–arms–trunk (HAT) angles, as well as on lower leg and COM angle (the orientation of the line from ankle joint to center of mass). It was found that the variance in knee and hip joint angles did not differ from the variance found in the ankle angle. The first PCA component indicated that, generally, the upper leg and HAT segments move in the same direction as the lower leg with a somewhat larger amplitude. The first PCA component relating ankle angle variance and COM angle variance indicated that the ankle joint angle displacement gives a good estimate of the COM angle displacement. The second PCA component on the segment angles partly explains the apparent discrepancy between these findings because this component points to a countermovement of the HAT relative to the ankle joint angle. It is concluded that postural control during unperturbed stance should be analyzed in terms of a multiple inverted pendulum model.

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